Randomized response technique: The procedure for collecting the information on sensitive issues by means of the survey, in which an element of chance is introduced as to what query a respondent has to answer. In the survey about abortion, for instance, a woman may be posed both the questions 'have you had an abortion' and 'have you never had an abortion', and is asked to respond to one or the other depending on the outcome of a randomizing device in her control. The response is now not revealing since no one except the respondent knows which question has been answered. Yet the data attained can be used to estimate the quantities of interest, here, for instance, the proportion of women who have had an abortion (π); if the probability of selecting the question 'have you had an abortion', P, is known and is not equal to 0.5. If y is the proportion of 'yes' answers to this question in a random sample of n respondents, one estimator of π can be given by the following formula
 
This estimator is unbiased and has the variance, V